package com.zsy.test.jm2;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;



/**  
 * <p>  
 * BASE64编码解码工具包  
 * </p>  
 * <p>  
 * 依赖javabase64-1.3.1.jar  
 * </p>  
 *   
 * @author IceWee  
 * @date 2012-5-19  
 * @version 1.0  
 */
public class Base64Utils {

    /**  
     * 文件读取缓冲区大小  
     */
    private static final int CACHE_SIZE = 1024;

    /**  
     * <p>  
     * BASE64字符串解码为二进制数据  
     * </p>  
     *   
     * @param base64  
     * @return  
     * @throws Exception  
     */
    @SuppressWarnings("restriction")
	public static byte[] decode(String base64) throws Exception {
    	return Base64.decode(base64);
    }

    /**  
     * <p>  
     * 二进制数据编码为BASE64字符串  
     * </p>  
     *   
     * @param bytes  
     * @return  
     * @throws Exception  
     */
    @SuppressWarnings("restriction")
	public static String encode(byte[] bytes) throws Exception {
    	return Base64.encode(bytes);
    }

    /**  
     * <p>  
     * 将文件编码为BASE64字符串  
     * </p>  
     * <p>  
     * 大文件慎用，可能会导致内存溢出  
     * </p>  
     *   
     * @param filePath 文件绝对路径  
     * @return  
     * @throws Exception  
     */
    public static String encodeFile(String filePath) throws Exception {
        byte[] bytes = fileToByte(filePath);
        return encode(bytes);
    }

    /**  
     * <p>  
     * BASE64字符串转回文件  
     * </p>  
     *   
     * @param filePath 文件绝对路径  
     * @param base64 编码字符串  
     * @throws Exception  
     */
    public static void decodeToFile(String filePath, String base64)
            throws Exception {
        byte[] bytes = decode(base64);
        byteArrayToFile(bytes, filePath);
    }

    /**  
     * <p>  
     * 文件转换为二进制数组  
     * </p>  
     *   
     * @param filePath 文件路径  
     * @return  
     * @throws Exception  
     */
    public static byte[] fileToByte(String filePath) throws Exception {
        byte[] data = new byte[0];
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            in.close();
            data = out.toByteArray();
        }
        return data;
    }

    /**  
     * <p>  
     * 二进制数据写文件  
     * </p>  
     *   
     * @param bytes 二进制数据  
     * @param filePath 文件生成目录  
     */
    public static void byteArrayToFile(byte[] bytes, String filePath)
            throws Exception {
        InputStream in = new ByteArrayInputStream(bytes);
        File destFile = new File(filePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);
        byte[] cache = new byte[CACHE_SIZE];
        int nRead = 0;
        while ((nRead = in.read(cache)) != -1) {
            out.write(cache, 0, nRead);
            out.flush();
        }
        out.close();
        in.close();
    }

}